Automatic traffic signal system



Aug. 9, 1938. F. J. BUECHEI., .JR

AUTOMATIC TRAFFIC SIGNAL SYSTEM Filed May 2, 1923 3 Sheets-Sheet 1 Aug. 9, 1938. F. J. BUECHEL, JR 2,126,614

AUTOMATICy TRAFFIC SIGNAL SYSTEM Filed May 2, 192s s sheets-sheet 2 Aug. 9, 1938. F. -J. BUECHEL, JR 2,126,614

` AUTOMATIC TRAFFIC SIGNAL SYSTEM Filed May 2, 1925 5 Sheets-Sheet 3 @Hiob/wan Franci Patented Aug. 9, 1938 AUTOMATIC TRAFFIC SIGNAL SYSTEM Francis Jpuechel, Jr.. Rochester, N. Y., assignor, by `mesneassignments, to Automatic `Signal Corporation, a corporation `of Delaware l application May 2.1928, serai No. l274,499

' viz claims. V(o1. 177-337) This invention relates to improvements in automatic traiiic control signals. The primary object of this invention is the provision of an improved automatic traic signal device adapted to be used at the intersection of crossing streets for automatically regulating the traflic on the street according to the relative positioning of vehicular tralc upon the streets.

Advantage has been taken in the present invention of the fact that cars travel in group formation upon busy streets whereon the travel is regulated by means of trafic signal lights. In each group of vehicles it will be noted that they travel in rather uniform spaced relation along the street as they approach the intersection, and that there is a considerable space between the last car of a line or group and the advancing car of the next group coming down the street towards the intersection. The present invention utilizes this fact, and suitable control mechanism is used for shifting signals when the space interval between cars is such that the elapsed time required for spaced vehicles to pass a predetermined location adjacent an intersection will be suiliciently great to warrant a change of signals.

A further object of the invention is the provision of improved automatically operated traiiic signal apparatus adapted to be placed at street intersections for regulating the changing of vehicle signals in accordance with the amount of vehicular travel and relative time spacing of the same upon the streets; the improved apparatus being entirely automatic in operation and embodying means for changing the signals after minimum and maximum periods of time, depending whether there is little or much vehicular trailic on the streets.

Other objects and advantages of this invention will be apparent during the course of the i'ollowing detailed description.

In the accompanying drawings, forming a part of this specification, and wherein similar refer ence characters designate corresponding parts throughout the several views,

Figure 1 is a diagrammatic representation of the wiring of the improved traiiic signals andfor travel of vehicular trailic across the intersection on the north and south streets. Figure 3 is a fragmentary view, partly diagrammatic, and in side elevation, of the control mechanism for the improved automatic traliic signal'arrangement.

Figure 4 is a plan view of an electro-magnetic operating apparatus for the control mechanism.

Figure 5 is a sectional view taken substantially onthe line 5-5 of Figure 3.

Figure 6 is a sectional view taken through a vehicle operated street switch.

In the drawings, wherein for the purpose of illustration is shown only a preferred embodiment of the invention the letters A and B may respectively designate intersecting east and west, and north and south streets, as shown in Figures l and 2 of the drawings. Lamp signals 69 and 10 maybe placed at the 'opposite sides of the intersection, at the eastern and western sides on'the street A. Similarly, lamp signals 1I and 12 may be placed on the street B, at the north and south sides of the intersection. These signals are of the two lamp type; the green light preferably being nearest the curb, and a red light oi. each being remote from the nearest curb. Other lightingarrangements maybe provided, if desired, and indeed these signals may be mechanically operated if desired. On the right sides of the street A `at opposite sides of the intersection, looking in the direction of travel of traffic towards the intersec- `tion, street switches 13 and 14 may be placed, and

in similar locations on the street B, street switches 15 and 16 may be placed on the northern and southern sides of the intersection. These street switches are adapted to cooperate in connection with the control mechanism of the invention subsequently described, in automatic regulation of 'the lights of the signal lamps BS to 12 inclusive. Dummy policemen 11 may be placed in the middle of each of the streets at each side of the street intersection, to insure that vehicular traffic will all pass over the street switches as the vehicles approach the street intersection.

In Figure 6 is Ishown a longitudinal section of one of the street switches, it being understood that all of the street switches 13 to 16 inclusive embodies the same construction. The length of the switches are arranged transverse or at right angles to the run of the street, and each includes a switch box 'I8EL sunk in the street, and providing a compartment therein normally closed by a movable plate or cover 18, the upper surface of which is arranged to lie ilush with the street surface. The switch box 18L is provided with shoulders 32 to limit the extent to which the plate 13 may be pressed into the box compartment. Normally spaced contacts 18 arid 30 are carried on the facing surfaces of the cover 13 and box 13i respectively, in insulated relation thereto, and connected in circuit .arrangement with the signal lamps in a relation to be subsequently described. Springs 3I hold the top plate or cover 18 so that the contacts are spaced from each other, and these springs have sufficient strength to allow only the excessive weight of an automobile to cause engagement of the contacts 13 and 30.

A control unit C is provided for regulating the opposed travel of traillc on the streets A and B in a minimum or a maximum time, depending upon the amount of vehicular tramo on the street and the maximum time which it shall be allowed to travel on any one street. This control mechanism C includes a frame work which 'is only partially shown, including upper and lower spaced stationary platforms D and E. A vertically positioned screw or spirally grooved shaft I has a bearing at its upper and lower ends in the platforms D and E, as shown in Figure 3 of the drawings, and the spiral groove therein extends from end to end and is continuous. A Prime mover or motor 45 is provided,v having a geared connecttion 45n with a drive shaft 2 arranged transversely below the lower end of the groove shaft I and below the platform E; bevel or miter gears 3 being'provided for gearing the drive shaft 2 with the groove shaft or screw I for drive of the latter. Rods 4, 5, 3 and 1 are supported in parallel relation with the grooved shaft I, in uniformly spaced relation thereabout, bearing at their upper and lower ends in the platforms D and E for oscillation. I'he upper ends of said rods extend above their upper bushings or bearings in the top platform D and are there provided with collars 3 which prevent the longitudinal moving of the said rods with respect to their platforms D and E. Trips or tracers 9, I0, II and I2 are vertically slidable upon the rods 4, 5, 6 and 1 respectively. as shown in Figures 1, 3 and 5 of the drawings. Each of these tripsis provided with a radially disposed pin I3 which projects radially into the groove of the shaft or screw I and is removable therefrom by reason of circumferential movement of the tracer or trip which respectively carries the pin. These pins I3 extend through the cylinder of the trips or tracers, into sliding engagement in vertical slots or grooves I3l which are provided in the rods for the respective pins I3. The pins I3 operating in the grooves of these rods 4, 5, 6 and 1 prevent the cylinder bodies of `the tracers or trips from turning on the rods, and for a purpose which will be subsequently described. l

The upper ends of the rods 4, 5, 6 and 1 extend above the top surface of the platform D and are there provided with rigid radially extending arms I4, best shown in Figure 4 of the drawings. On the top surface of the platform D are provided solenoids I9, 20, 2I and 22, which respectively slidably support armatures I5, I6, I1 and I3. These armatures are respectively pivoted at their outer ends to the outer ends of the arms I4 of the rods 4, 5, 6 and 1 in order that when the solenoids are energized the respective armatures will be drawn in and the rods 4, 5, 6, and 1 turned slightly on their axes. Inasmuch as the trips or tracers 9, I 0, II and I2 are slidably positioned upon these rods against rotation, it is apparent that the pins I3 thereof will be disengaged from the groove in the upright shaft or screw I when the solenoids are energized-to permit said trips or tracers to drop on the rods on which they are slidably positioned, to the bottom platform E. Springs 23, shown inFigure 4 of the drawings, hold. the arms I4 against stop pins 24, and in this position, with the solenoids de-energized the trips will havetheir pins I3 engage in the groove of the screw or shaft I. g

In spaced relation with the rods 4, 5, 5 and 1, and in respective diametrically opposed relation from the screw or shaft I, other rods 25, 23, 21 and 23 are provided, as shown in Figure 5 of the drawings, 'and elsewhere, which are parallel with the'shaft I and the rods 4 to 1 inclusive, and bear at their upper and lower ends in the platforms D and E for reciprocation in said platforms, so that the upper ends thereof may be extended above the upper surface of vthe platform D for operation of certain switches for a purpose to be subsequently described. 'I'hese last mentioned rods respectively support adjustable knobs 30, 3|, 32 and 33, which are cylindrical in formation and are adjustably clamped to the respective rods by `means of set screws 32", more particularly shown in Figure 3 of the drawings. Each of these knobs is provided with an annular flange 33Il thereabout, which the trip or tracer slidable on the adjacent rod is adapted to engage when the tra'cer has been elevated by the groove screw I sufficiently to engage the flange 33, and thus to force the respective rod 25, 25, 21 or 23 at its upper end through the platform D for switch closing purposes, to be subsequently mentioned. At the upper ends the rods to 23 inclusive are each provided with an enlarged insulation head 33 which holds the rods from falling thru the platform D and serves the additional purpose of insulating the switches 31, 33, 3l and 40 from the respective rods 25, 26, 21 and 23. I'hese switches 31 to 40 inclusive are mounted on the top of the platform D and are each comyarms 4I of the respective switches, and press the same into engagement with the upper switch arm 42 for closing a circuit for purposes which will be subsequently described.

As part of the control mechanism, a cam 44 is provided, having five grooves 44, 44h, 44", 444, and 44 thereinf The grooves 44* and 44b extend about 90 around the circumference of the cam 44, in diii'erent planes. The grooves 44 and 44d extend about 180 about the circumference of the cam 44 in different planes. There are two of the grooves 44e, of crescent shape formation, each slightly less than 180, and located in the same plane. These cam grooves are more particularly shown in the sectional views thru the cam 44, in Figure 1 of the drawings. The cam 44 is keyed upon a shaft 2*. Rotatable and slidable on this shaft 2" is a sprocket wheel 41, which is connected with a sprocket Wheel 41Il keyed on the shaft 2 by means of a chain belt 45. The sprocket Wheel 41 has a clutch part 43 thereon adapted to mesh with a clutch part 48 keyed on the shaft 2. The clutch for keying the cam 44 on the shaft 2l` includes a clutch lever 50 pivoted at 53 intermediate its ends; a spring 49 being pro-v parts 48 and 48", asshown in Figure 3 of the drawings.' The clutch lever 58 is really an armature for the electromagnets 5|, which are mounted upon a suitable frame 5|-, and in a circuit for the purpose of attracting the armature to rotate the cam 44 in order to shift the signals on the streets at an intersection, in a relation to be subsequently described.

Plungers or rods 54 are slidably positioned upon a supporting block 55 above the cam 44, having ends which extend for operation in each of the grooves 44, 44D, 44C, 44d and 44e of the cam. These plungers are held against the cam 44 by means of springs 55e. At its upper end above the block 55 each of the plungers has an insulaswitch arm 64, which is also carried by the block 68, operates to alternately engage and close circuits through the switch arms 63 and 85. The switch 62 includes the top spring switch arm 66 secured in an insulation block 68, and a second switch arm 61 mounted on this block 68, and at its opposite end connected with the insulation cap 51 of the slide plunger 54 which operates in the grooves 44e of the cam 44, as shown in Figure 1 of the drawings.

As part of the operating circuit there are iive sets of electro-magnets which cooperate in circuit regulating relation with the solenoids I9 to 22 inclusive. 'I'hese sets of electro-magnets comprise a set consisting of two electro-magnets 83 having upper and lower armatures 84 and 85 cooperatingtherewith; the upper armature when attracted by the electro-magnets 83 engaging four contacts 86, 81, 88 and 89. The bottom armature has one-contact 98 which it engages when attracted by the electro-magnets 83. The second set of electro-magnets 9| has also upper and lower armature 92 and 93 respectively, each of the same having one contact which it engages when attracted by a magnet. Thus the armature 92 has a contact 94 and the armature 93 has a contact 95. The third set of electro-magnets 98 has upper and lower armatures 91 and 98; the upper armature 91 having contacts 99 and |88 which are engaged when the armature 91 is attracted by the velectromagnets 96. The lower armature 98 has a single contact I 8| which is engaged when the lower armature is attracted by the magnets 96. The other set of electro-magnets |82 has also upper and lower armatures I 83 and |84. The upper armature |83 has contacts |85 `and |86 which are engaged when the armature is attracted. The lower armature |84 has a single contact |81 which it engages when the lower armature is attracted by the electro-magnets |82. Normally the armatures 84, 85, 92, 93, 91, 98, |83 and4 |84 are disengaged from their contacts, with the electro-magnets thereof de-energized, and the armatures held against stops |88 by means of springs |89 which individually actuate the same to move them away from the electro-magnets. Another set of electro-magnets |.I8 is provided, which are controlled by the switch B2 ina manner to be subsequently described, for shifting current in a coopera-tive relation with the electro-magnets,

83 as will be subsequently described. This set of electro-magnets I I8 has a single armature III.

normally held in engagement with a contact |I2 by means of a spring ||3 when the electromag- `nets ||8 are de-energized. When energized the electro-magnets I|8 draw the armature III into engagement wlth'another contact ||4 provided therefor, and for a purpose to be subsequently described.

As before mentioned, the operation of the signal is dependentupon the elapsed time necessary for spaced vehiclesV traveling toward an intersection from the same direction to reach ai predetermined point adjacent the intersection. When the group of vehicles traveling on the street with the "go signal are closely spaced as they approach the intersection the signallight will remain thus until the spacing of the vehicles at opposite sides of the intersection, on the street which has the go signal set are such that a change is desirable in the signals. The travel of vehicles ona street may be so light and the vehicles so irregularly spaced thereon that it is desirable for'the signal' go to remain on for minimum time.' Also, it may be desirable that a switch in signals occur if the travel of vehicles is so` heavy on the street y that after a maximum time a change in the signal lights should occur. 'I'he control mechanism takes care of all of these features. The control parts may be conveniently divided into several parts as follows:- I

One of the street controls may. include the rod 4, its tracer 9, the rod 25, its knob 38, the switch 31, solenoid I9 and electro-magnet 96.'

Another street light control mayinclude the rod 5, with its trip or tracer I8, the rod 26 with its knob 3|, the switch 38, solenoid 28 and electromagnets |82. A

A third control which may be conveniently termed the minimum control, may include the rod 6, with its trip II, rod 21 with its knob 32, switch 39, solenoid 2|, and electro-magnets 9|.

The fourth control which may be conveniently ltermed the maximum control may include the rod 1 with its trip I2, rod 28 with its knob 33, switch 48, solenoid 22, and electro-magnets 83.

With the motor running the drive shaft 2 is rotated and due to its geared connection, the shaftY I is rotated. Normally the pins I3 of the trips 9, I 8, II and I2 engage in a groove of the shaft I and by reason thereof the trips 9, I8, I I and I2 will elevate along their rods 4, 5, 6 Vand 1 respectively, until they engage the flanges of the knobs 38, 3|, 32, or 33. 'I'he knobs v38 and 3| are fastened on the rods 25 and 28 at a certain height by means of thumb screws 32e so that it will take the trips 9 and I8 the same time to rise from the against the top arms 42 thereof, and closing said'L switches. The time elapsing for the climbing upwardof the trips 9 and I8 on their rods is determined upon according to the time which elapses between the passing of cars over the street switches. At dull times of the day the minimum control establishes a minimum time that the signals are to remain on and off. For example, this may be established at eight seconds, as determining the time between changes of signals, entirely independent of the extent of vehicular traiiic. The knobV 32 which forms parts of the minimum control is set at a certain height on the rod 21,

and raise it slightly, to close the members of the switch 3,3, causing electricity to pass through the said switch. For various reasons it is desirable to limit the passing of traffic to a certainlength of time, say thirty seconds independent of the extent of vehicular traillc. 'Ihe maximum control has the knob 33 set at a certain height on the rod 2l, so that itwili take the tracer |2 thirty seconds to rise from the bottom platform and trip the `knob 33 to raise the rod 23 sufiicient to close the switch 4l. y s

The closing of the4 circuits throughout the various solenoids,lelectromagnets, and switches will be referred to during the description of the operation. A generator or source of current III'A is provided, from which positive and negative wires |23 and I I1 respectively lead on into the wire system, and from these main wires I1 and |23 various branchecircuits are provided to the dierent details of the system. Referring to the switch I3 which controls the red and green signal lights of the signal lamps 63 and 10, it will be notedlthat the member 34 of this switch $3 is connected to a positive wire IIS which branches oif from the main positive wire |23. With the details as arranged in Figure 1 for travel of traillc on the east and west streets of the intersection, the center arm 64 is making contact with the bottom member 35 o f the switch. This bottom member y 3l is connected by the wire IIS to the green lamps of the signals 39 and 10; these lamps, as weil as the red lamps of the signals 33 and 10 being supplied with negative current from the wire II1 as shown in the circuit. It is therefore obvious that with the switch 53 in this position the green lights will be illuminated and indicate to trafilc the clear passage across the intersection on the street A, or in an east and west direction. 'I'he switch I! controls the flashing of the green and red lamps on the signals 1I and 12 for controlling traillc on the north or south streets B across the intersection, and inasmuch as the center arm 64 of this switch is connected to the positive current wire I II, and is making contact with the upper switch arm 63, the red signal lamps of the signais 1I and =12 will be illuminated for stopping passage of traillc on the street B across the intersection. It is of course apparent that the switches 33 and l! are thus positioned by reason of the riding of the plungers 54 on the cam 44 with respect to the grooves provided for these respective switches.

The switch 60 controls the ow of current into the system through the street switches 14 and 13. With the plunger 54 in the groove 44" of the cam 44, as shown in Figure 1, the center member 34 of the switch 60 is making contact with the bottom arm 65,. This center member 64 of this particular switch is connected by a wire I I9 to the solenoid I3 which forms part of the street control system, and the bottommember 65 of this switch is connected by a wire to the street switch 14 on the street A. Negative current is supplied to the switches 14 and 1 thru the wire I I1 as shown.

The switch 6| controls the ilow of current through the switches 13 and 15. As shown in Figure 1, the plunger 54 of this switch 6| is operating in the groove 44d of the. cam 44, and pulls the center member 64 down into contact with the bottom switch arm 65. 'Ihe center member 64 of this switch is connected by a wire I2I with the solenoid 20, forming part of .the street control mechanism. The top arm 63 is Referring' further t'o the operation, with'the y knobs u, u, n and u ci' the control mechanism IC set in their proper position, and the street switches 13 and 14 in position to be closed by vehicular trame in order to operate details of` the control mechanism; the tracers 3, Il, |I and |2, at the instant that 4the green lights dash in the signals and 1l all begin to rise simultaneously from the bottom platform E, inasmuch as, vthe pins I3 thereof operate in the groove of the shaft I. Every time that a vehicle vpasses over the street switch 14, contact is made and a cirvcuit from this switch 14 closes thru the wire III, wire |20, switch 3l in its lower position, wire III, and solenoid I3. The solenoid I3 receiving positive current at all times from wire |23 becomes energized and draws in its armature I5, and by reason of the arm connection I4 a slight turn is given to the control rod 4. The turn is sutllcient to remove the pin I3 of the trip 9 from the groove of shaft permitting the trip or tracer 3 to drop against the bottom platform E, from the position to which it had climbed on the rod 4, prior to the time that the vehicle crossed the street switch 14. Every time that a contact is made in the switch 14, with the cam 44 set as shown in Figure 1, this operation will take place.

Similarly, when a contact is made in the other street switch 13 of the east and west street A, current flows through the wires II1 and |22 leading therefrom, to the closed portion (see Figure 1) of the switch 6I, into wire I2I and into solenoid 2li. This solenoid 20 receives its current from wire I 23 at all times, and upon energization it draws itsy armature I6 thereinto, and through the arm I4, a slight turn is given to the rod 5, suiiicient to remove`the pin I3 of the trip or tracer I0 from the groove of the shaft I, and permitting the tracer I Il to drop to the bottom platform E, from the height to which it has elevated prior to the time that the vehicle passed over the street switch 13. Of course as soon as the vehicle leaves the switches 13 and 14 the current is broken in the circuit therewith and the springs 23 will pull the solenoid-cores back into theirposition shown in Figure 4, and throw the pins I3 of the trips 9 and Ill into the groove of the shaft and the trips 3 and Ill again begin to rise upon their respective rods; it of course being understood that the shaft I is rotating all oi' the time. So long as the total time required for each of the tracers 9 and I0 to reach and slightly lift their respective knobs 3U and 3|, is longer than the time which elapses between successive operations of the respective street switches by the rear of one car and the'iront of the next car following, in the line of cars approaching the same, the said tracers or trips 9 and II! will not reach their respective knobs 30 and 3|. However, when the time interval of street switch operation by successive cars passing the signal becomes greater than the predetermined time, the trips will operate against the knobs 30 and 3|, for achieving the results mentioned.

Assuming that there is a large amount of traillc passing in both directions on the street from the diagrammatic wiring in Figure 1.

A. AIi' the minimum control is set for eight seconds, and 'the trame has been passing across the intersection on the street A forthis'length of time, the tracer will reach and lift the knob 32, and inasmuch as thelatter is fastened to the rod 21, said rod will be lifted and pressed against the member 4I of the switch 39, pressing against the top member 42, and thus closing this switch. The bottom switch arm 4| receives negative current from the wire ||1, asshown in the operating circuit in Figures 1 and 2 of the drawings. and the contact in the` switch 39 being made, the current will pass from wire ||1, thru the switch 39, into wire |24, and into the set of electro-magnets 9|. IPositive current is received by electro-magnets 9| from wire |25, switch contact II2, armature III, and wire |23, energizing the magnets 9| and causing the armatures 92 and 93 to close against their respective contacts 94 and 95. Simultaneously with the energizing of electro-magnets 9|, the solenoid 2| is energized, receiving negative current from wire e |I1, switch 39, wire -I24, and positive current at all times from wire |23, as can be understood Contact 94 is connected with the negative current wire ||1, and the armature 92 engaging contact 94 will permit the negative current to pass into armature 92 and into wire |24, from which the electro-magnets 9| and solenoid 2| now receive a supply of negative current. Remembering now that as soon as solenoid 2| became energized, the armature I1 was drawn in and the rod 6 slightly turned, removing the pin I3 of tracer from the grooved shaft I, and permitting thetracer II to drop to the bottom platform E, it is apparent that knob 32 and rod ,21 fastened thereto will likewise be permitted to drop the distance they were raised, and the members 4| and 42 of the switch 39 become disengaged, opening this -switch and permitting the circuit through the 'intersection within a predetermined elapsed time and by which the streetfcontrols were set, the tracer 9 will have ample time to rise and .reach its knob 30, and lift it slightly, causing the rod 25 keyed therewith to ride and press the bottom 'arm 4| of the switch 31 against the top arm 42 thereof.` This of course happens because the street switch 14 was not operated soon enough by vehicular trailc to cause a trip of the tracer -9 prior to the time that it caused closing of the switch 31. In this switch the bottom arm 4| receives negative current from Wire |I1, which passes into wire |26 and into the set of electromagnets 96. Positive current is received bythese electro-magnets from wire.|25 through contact ||2, armature ||I,'and lines |23, and energization of thel electro-magnets 96 will cause the armatures 91 and 98 thereof to engage the respective contacts 99, |00, and provided therefor, as shown in Figures 1 and.2 of the drawings, Since armature 91 engages contact 99, negative current from Wire |26 passes through armature 91 into contact 99, and into wire |21 and thus into wire I I9, and into solenoid I9., which now becomes energized, inasmuch as it receives positive current from wire |23, at all times. The

contact |00 is directly "connected with negative current supply wire I1, and inasmuch as armature 91 engages the same at this time, negative current passes to contact |00 into armature 91,

as soon as solenoid I9 was energized, and rod 4 turned, the tracer 9 became disengaged with shaft I permitting it to fall to the bottom platform E, and likewise permitting knob 30 and its rod 25 to drop and release the contactsof switch 31.

Were it not that the negative current is now supplied from contact |00, the electro-magnets 96 and solenoid I9 would not remain in a state of energization, as they now should.

A similar operation occurs when the spacing `of the vehicles in the street A, passing .westwardly over the intersection is such that the tracer I0 has ample time to rise and trip the knob 3| before the next vehicle operates the street switch 13 to prevent such operation. Tripping of the knob 3| elevates the rod 26 and engages the contacts 4| and 42 of the switch 38, negative current then passing from wire II1,

through the closed switch 38 into wire |28 and into the electro-magnets |02, for energizing them. Positive current is of course received by these electro-magnets |02 from wire |25. Upon energization the electro-magnets will attract the armatures |03 and |04 for engaging the contacts |05, |06, and |01 in their respective relations. The armature |03 engaging the contact |05, permits negative current to flow from wire |28 through the armature |03 into Contact |05, and through wires |29 and I2| into solenoid 20. This solenoid is energized, receiving positive current from wire |23. Contact |06 being directly connected with negative current wire II1, with the .armature |03 engaging the same, the current will pass therefrom into wire |28, from which electro-magnets |02 now receive their negative current. Solenoid now receives this negative .current from' contact |06, inasmuch as the negative current from contact |06'passes through wires |29 and I2I in the relation above described, and maintains the solenoid 20 energized; this being necessary since as soon as it was energized the rod 5 was turned and the tracer I0 permitted to drop, to disegage the contacts of the switch 38 through dropping of the rod 26. Thus, notwithstanding the opening of the switch 38 the electro-magnets |02 and solenoids 20 remain energized.

From the above it will be apparent that the electro-magnets 9|, 95 and |02 are now all energized, and attracting their respective armatures 93, 98 and |04 in engagement with the contacts 95, |0I and |01 respectively provided therefor. This permits current to flow from the wire II1 through these various armatures and contacts into electro-magnets 83, which now become energized, inasmuch as they receive positive current from the wire |25. It will be noted that al1 three sets of armatures 9|, 96, and |02 must be energized with their contacts before negative currentv is permitted to enter the electro-magnets 83.

Upon energizing of the electro-magnets 83, the` therefor. The armature 84 engages the contacts 88, 8l', 88 and 89, and the amature 85 engages the contact 90 provided therefor. -Inasmuch as armature 84 is connected with the wire ||1 for receiving negative current therefrom at alltimes,

it is apparent that itwill pass the same onto the contacts 88,81, 88 and 89 upon energizing of the electro-magnets 83. From contact 88 the negative current goes into the wire |30, through electro-magnets 83, and solenoid 22, energizing the latter, and releasing its tracer I2 which has not yet reached the knob 33. Since contact is directly connected with the positive current wire |23, current from this wire now passes thru contact 98, armature 85, wire |3I, and -into electro-magnets 5| which control the clutch of the cam 44, energizing the electro-magnets 5|, and attracting the armature 50. This moves the clutch part 48 intoengagement with the clutch part 48e, and engages the clutch for keying the cam 44 to theshaft 2*. The cam 44 now revolves, and makes nearly one-half of a revolution. During this turn the plunger 54 for the switch 82 will rise from the groove 44* in Which'it reposed, towards the outer surface of the cam 44, until the switch members 88 and 81 of the switch 82 engage. The switch member 81 of said switch is directly connected to the positive current wire |23, and the current therefrom passes into the switch arm 88 and into the wire |32, and into electro-magnets I 0, to energize the latter, inasmuch as they are connected to circuit ||1. Electro-magnets |I0 now draw the armature III thereof from contact ||'2 over to its other contact I I4. This breaks the circuit thru the electromagnets 83, 9|, 98 and |02, and de-energize the same. All of the armatures of these electromagnets 83, 9|, 98 and |02 are now pulled by their springs |09 into engagement with .stops |08, to their normal inoperative position, and it is thus apparent that the current thru the solenoids I9, 20, 2| and 22 will also be broken, permitting the rods 4, 5, 8 and 1 with their respective trips or tracers 9, I0, and I2 to be pulled bysprings 23 for a short arcuate movement, until the arms I4 engage the stops 24, engaging the pins I3 of these trips 9, I0, and |2 in the groove of the shaft I, and resetting the trips for movement along their respective rods. y

When the armature III was shifted as above described upon energization of its electro-magnet, the current was broken in electro-magnets 83. This allows the armature 'to disengage from contact 90. This breaks the current in electromagnets 5I, and the clutch disengages before the cam 44 makes a complete half revolution. The cam stops at a point where the plunger 54 of the switch 82 is still on the outer edge of the cam 44. However, armature I engaging contact ||4 sends positive current to wire |3| and into electro-magnets 5|, permitting the clutch to remain engaged and the cam 44 to finish its half revolution. As soon as the cam 44 finishes its half revolutionV the plunger 54 of the switch 82 drops into the abrupt end` of one of the grooves 44, disengaging the switch arms of the switch 82. The positive current through'the electro-magnets I|0 is then broken and the amature is pulled back against the contact I|2 by means of the spring II3, breaking the current through electro-magnets 5| and permitting the clutch 48 to disengage and stop revolution of the cam 44.

The above operation of the cam 44 for a half' the upper arm 83, andas the upper arm 83 is connected by'wire |33 through the red signal lamps of the signals 88 and 10, the latter are operated on the streets A for stopping travel oi' traffic thereon across the intersection. For the switch 59 the center arm 84 has been moved into engagement with the lower arm 85, by'reason of the dropping of the plunger 54 of said switch into the groove 44h, and as the bottom member 85 of this switch is connected by wire |34 to the green signal lamps on the signals 1| and 12, the latter are thus operated to indicate to trailc on the streets B that it may travel across the intersection. In the switch Si: the plunger 54 thereof has been elevated to the outer periphery of the cam 44, so that the center arm 84 now engages the upper arm 83 thereof, and as the upper arm 83 is connected by wire |35 to the street switch 18, the latter upon depression Will operate a circuit through the switch 80 including the details above described. In the ^switch 8| the plunger 54 has been elevated to the outer periphery of the cam 44, to engage the center contact 84 with the arm 83, sending the current thru wire |38 tothe street switch 15, so that upon depression of the latter the current Will'be closed thru the contacts of the switch 8| as thus engaged for operating details of the control mechanism in .the cycle above described.-

The signal now has completed one half of the cycle and it is ready for travel of traftlc on the street B across the intersection. While the cam 44 is making its half revolution during the signal switching operation, it will be noted that for a short time the red lights are showing in all the signals 89 to 12 inclusive, by reason of the design of thecam groove 44a and'44b, which are only approximately 80 in length, so that during about a 90 travel of the cam 44 all of the red signals will be on which permits ample time for the vehicles and pedestrians who have started across the intersection to pass the signal before the switch in red and green signals takes place.

The above operation contemplates the condition where traflic on the streets having the right of way has crossed the street switches within the` predetermined time so that the street controls have not been able to operate duringthe minlmum period, but that sometime between the operation of the minimum control and before the expiration of the thirty-secondl maximum period, traffic has become so straggly as to permit a trip operation 'of switches signals. Automatic periodic alternation of the right of way to the respective streets is determined by operation of the minimum controls when heavy traffic approaches the street intern ,sectionI too late to reach the street switches before their controls have operated and before the minimum control has operated. However, if the vehicles passing along the street A are closely spaced so that the street switches 13 and 14 will be operated continuously, or at least one of them operated without permitting the trip operation of the switch 31 or 38 therefor, at the end of the Ythirty second period the tracer or trip I2 will reach the knob 33, and lifting the rod 28 will contact the arms 4| and 42 of the switch 40, for closing the latter. Inasmuch as its'switch arm 4| is directly connected with the negative supply wire II1, this current will pass through the wire I 30 into the electro-magnets 83, with the result that they will be energized. Negative current from armature 84 is sent through the contacts 88, 81, 88 and 88, which in turn delivers the cur- 31 and 38 and a change in rent to'electro-magnets 83, 9|, $8 and |02 respectively, engaging their armatures with their contacts, and thence to the /solenoids i9, 20, 2| and 22, disengaging all tracers from the groove in the shaft I, and the same operations follow as above described for a shifting in the signals.

'Thus if the maximum control is set for a cer-- there is no traiilc on either street A.-or B, the

right of way indication is given alternately from one street to the other. remaining on each street for a period of time equal to the time at which the minimum control is set, which is eight seconds. Thus, as soon'as the right of way indication is given to a street, the trips or tracers of both of the street controls commence their upward movement. Since there is no trailic to actuate the street switches and thus cause a resetting of the street controls, which `means a loss in its upward movement, they will reach their complete prededetermined upward travel and thus cause an operation of their respective electro-magnets in,-

` .the street controls have actuated their respective electro-magnets, it will only be necessary for the .minimum control to cause an operation of its respective electro-magnets tol cause a change in signals. Since the minimum control is set atl eight seconds, this change in right of way indicationwill occur eight seconds after the previous change in signals, which will be iive seconds after the street controls havecompleted Atheir particular function. The same-will then continueb with the other streets, etc., alternately from Vone street to the other for periods of eight seconds each. The signals will operate in this manner so long as there is no trafiic present on the street.

' `When an A street switch actuation is followed within eight secondsby aB street switch actuation nothing will happen so f ar as signal change is concerned. In this connection it must be remembered that the street which has the right of way, also has its street switches connected -with the street controls; the street switches of the other streets being disconnected. Any actuation .be a change in signals.

occur, giving the street B the right of way, then the actuation of the B` street switch, since the B street switches are now connected with the street controls because of the street B now having the right of way, will reset its particular street control, giving it a fresh start in its upward movement.

Assuming that street A has the right of way indication, which is maintained as such on account of continuous closely spaced switch actuations on A street. Ii?` said actuations continue for thirty seconds, at the end of this period the maximum control will function, since it is set at thirty seconds. Notwithstanding the fact that the street controls have not operated their respective electro-magnets on account of the closely occurring A street switch actuations, there will Since street A has the right of wayits street switches arev connected with the street controls: the street switches of street B being free and disconnected. Hence if actuation of a switch on B street occurs 15 seconds, let us say, after the rst switch actuation on A street, nothing will happen to change the signalling, since the B street switch actuation willl have no effect. f

If B street has the green or right of wayinthenin' operative relation with the B street switches, since the latter4 has the go signal.

The advantages embodied in the present invention of connecting each switch separately to an operating mechanism are generally as .followsz- First-Such .an arrangement is particularlyv Ladapted for operation at intersections of main of them does not produce any eiect on the signal A mechanism. It`will be observed that the same street controls are used in operative relation with the street switches in both streets; said street controls being shifted from one set of street switches to the other set with the changing of the right of way indications. Thus, when the street switches of one street are connected with the street controls, the street switches in the other street are free and disconnected and it is obvious that if street A has the right of way any actuation of the street switches in 'street B will not produce any effect on the signalling mechanism. However, if during the time elapsed between the last actuation of the A street switch and the B street switch, a change in signals should streets or highways, where traffic is relatively heavy'on both streets, whereas signals which have the switches in the same street connected to a single operating mechanism are useful -only where a mainstreet intersects with a subordinate street and thus are not efficient controllers of tramo where two main streets intersect.

vSecoml.-'I'he operation of the signal is directly` controlled by the density of traic approaching each side of the street, effecting a more uniform land accurate regulation of traiiic and accomplishing this in a quicker and more efilcient manner than is possible if the street 'switches were connected to one operating mechanism. In the pres.. ent arrangement traiic must be relatively heavy on at least one side of the street having the right of'way indication to hold said indication, else a change in signals will occur. In signal arrangements where the street switches are connected to one operating mechanism a straggling car from one side of the cross street,and then another straggling car from the other side occurring Within the predetermined time will keep the right Jof Way on said cross street. In the present arrangement cars must pass in a continued stream, each within the predetermined time interval of the preceding car, from at least one side of the street to hold the indication on said street. A straggling car from one side and then another straggling car from the other side, even if within to travel in groups, with greater distances between the successive groups than occur between .the vehicles of any one group. The operation is not, however, dependent upon the group traveling of vehicles, but operates according to the time interval with which the street switches are operated by vehicular trailic.

Various changes in the shape, size, and arrangement of parts may be made to the form of the operating circuit and details of the invention herein shown and described, without departing from the spirit of the invention or the scope of 'the claims.

I claim:

1. Ina trailic signal system the combination with a pair of intersecting streets, a right of way indicating means for each of the streets at the intersection, a vehicle actuated switch inA each street at each side l of the intersection, a cam, switch means operated by the cam for operating the right of way indicating means, a control unit including a plurality of normally open switches', means adapted to close the switches after the passage of a predetermined interval of timefincluding solenoids for tripping said means to prevent closing of the switches, said solenoids being normally inoperative, means electrically connecting the solenoids with the vehicle actuated street switches, including the switch means operated by the cam above mentioned, means for -actuating the cam including an electro-magnetically operated clutch, and means connected between said normally open switches and the electro-magnet of the electro-magnetically operated clutch for causing an engagement of the clutch upon closing of a predetermined number of the normally open switches. v

2. A trafilc control system for the intersection of'two streets with each `street having two opposite approaches to the intersection, including in combination, electric rlght'of way signals for the respective streets, cyclicswitch mechanism having alternate switching positions for energizing the respective signals alternately, a vehicle actuated 'device in each approach of each street. a constantly rotating threaded central shaft, three other shafts arranged parallel and closely adjacent to the central shaft each such other shaft being slotted along its length collars fitted on said other shafts to slide freely along the length thereof and having projections engaging vthe slots of their respective shafts and adapted normally to engage also the thread of said central shaft to be driven along their respective shafts from one end towardv -the other over a time period and adapted to be disengaged from said central shaft and returned to said one end when their respective shafts are turned axially, contact members positioned to be actuated by the respective collars upon the latter having been driven from the end of the shafts for certain distances along such shafts by engagement with the central shaft, electromagnetic means adapted to be energized by actuation of the respective contact members to turn the respective shafts and disengage the respective collars from said central shaft and including switch means operated by actuation of the respective contact members and maintained operated after each individual actuation thereof until all three contact members have been `actuated to then shift said cyclic mechanism from one position to the other, switch means operated by said cyclic mechanism in being so shifted to deenergize said electromagnetic means again, and. further switch means. operated by said cyclic mechanism for connecting the electromagnetic means for two of said other shafts respectively to the respective vehicle actuated devices of the two approaches of one street while the right of way signal therein is energized to be energized momentarily by momentary actuation of their respective devices to return their associated collars momentarily to said one end of the respective shafts.

3. A traffic control system as in claim 2 and additionally including a fourth shaft, collar and contact member of the same character as said other three shafts, with the last named contact member positioned further along its shaft than the other contact members, and additional electromagnetic means energized directly by said last named contactmember when .the latter is actuated by its collar to shift said cyclic switch mechanism to said other position if it has not already been so shifted by the ilrst mentioned electromagnetic means and also to turn said fourth shaft and collar to return the latter collar to the corresponding one end of its shaft.

4. A traffic control system forintersection of two streets with each street having two opposite approaches to the intersection, including in combination, right of way signals for the respective streets, cyclic operating means `for said signals and having alternate operating positions to indicate right of way alternately to the respective streets, a vehicle actuated device in each approach of each street, two time controlled switch means initiated by said cyclic operating means in said one position and operating at definite times from vsuch initiation, means associated with the cyclic operating means for connecting said additional time controlled switch means with the respective vehicle actuated devices in the respective approaches of said one street having right of way so as to reinitiate timing of the switch means for one approach by each actuation of the vehicle actuated device therein, and means including both said time switches and dependent on operation of both such switches at completion of their time periods to shift said cyclic operating means to its other position to'indicate right of way to the other street.

5. A traiic control system as in claim 4 additionally including a maximum time controlled switch means initiated by said operating means in said one position and operating at a considerably longer time period than the other two time controlled switch means to shift said operating means to said other position if the latter hasv not already been so shifted by operation of said other time controlled switch means.

6. A traffic control system for the intersection of two streets with each street having two opposite approaches to the intersection, including in combination, iight of Way signals for the respective streets, cyclic operating means for said signals and having alternate operating positions to indicate right of way alternately to the respective streets, a vehicle actuated device in each approach of each street, minimum time controlled switch means initiated by said cyclic operating means when the latter is in one position to indicate right-of wayto one street and operating at a minimum time from such initiation, two additional time controlled switch means initiated by said cyclic operating means in said one position and operating at a time from such initiation shorter than said minimum, means associated with the cyclic operating'means for connecting said additional time controlled switch meansl tionally including a maximum time controlled switch means initiated by said cyclic operating means in said one position and operating at a considerably longer time than said minimum from suchinitiation to shift said operating means to said other position if it has not already been so shifted by`operation of the other time switch means.

8. A traiiic control system for the intersection of two streets with each street having two opposite approaches to the intersection, including in combination, right of Way signals for the respective streets, cyclic operating means for said signals and having alternate operatingpositions to indicate right of way alternately to the respective streets, a 'vehicle actuated device in each approach of each street, two time controlled switch means initiated by 'said cyclic operating means in said one position and operating at definite times from such initiation, means associated with the cyclic operating means for connecting said additional time controlled switch means with the respective vehicle actuated devices in the respective approaches of said one street having right of way so as to reinitate timing of the switch means for one approach by each actuation of the vehicle actuated device therein, means including both said time switches and dependent on'operation of both such switches at completion of their time periods to shift said cyclic operating means to its other position to indicate right of way to the other street, and means individual to each of said time switch means to maintain the respective switches operated upon and after completion of their respective time periods and until said shifting means operates, irrespective of further operation of the vehicle actuated means con nected to the time switch means during such right of way on said one street.

9. A trailic control system for the intersection of two streets with each street having two opposite approaches to the intersection, including in combination, right oi way signals for therespective streets, cyclic operating means for said signals and having alternate operating positions to .indicate right of way alternately to the respective streets, a vehicle actuated device in each approach of each street, minimum time controlled switch means initiated by said cyclic operating means when the latter is in one position to indicate right ofway to one street and operating at a minimum time from such initiation, two

additional time controlled switch means initiated by said cyclic operating means in said one position and operating at a time from such initiation shorter than said minimum, means associated withthe cyclic operating means for connecting said additional time controlled switch means with therespective vehicle actuated devices in the respective approaches of said one street having right of way so as to reinitiate timing of the switch means for one approach by each actuation of the vehicle actuated device therein, means including said minimum timel switch and'both said additional time switches and dependent on operation of all three of these switches at completion of their time periods to shift said cyclic operating means to its other position to indicate right ol.' way to the other street, and means individual to each of said time switch means to maintain the respective switches operated uponA and after completion of their respective time periods and until said shifting means operates to shift said cyclic operating means to said other position.

10. A traiic control system as in claim 9 additionally including a maximum time controlled switch means initiated by said cyclic operating means in said one position and operating at a from such initiation to shift said operating means to said other position if it has not already been` so shifted by operation of the other time switch means.

11. A traiilc control system for the intersection of two streets with each street having two opposite approaches to the intersection, including in combination, electric right of way signals for the respective streets, cyclic switch mechanism having alternate switching positions for energizing the respective signals alternately, a vehicle actuated device in each approach of each street. three time delayed switch means connected to have their timing initiated by said cyclic switch mechanism when the latter is in one position energizing the right of way signal on one street and adapted to operate their respective switches at completion of their respective timing, the ilrst of said switch means having a time period serving as a minimum for said cyclic switch mechanism in said one position, and the other two switch means having timing periods shorter than such minimum, switching means associated with said of said one street in said one position of said cyclic switch mechanism to reinitiate either one ct said other time switch means by each actuation of its connected vehicle actuated device to delay completion of its time period, and means including the switches of said three time switch means and operative only when all said three switches are concurrently operated to shift said cyclic vswitch mechanism to its other position to energize the right of way signal for the other street.

12. A trame control system as in claim il additionally including a maximum time controlled switch means initiated by said cyclic operating means in said one position and operating at a considerably longer time than said minimum from such initiation to shift said operating means means.

FRANCIS J. BUECHEL, Jlr. 

